Numbers / 441

The Number 441

441 is composite: factorization 3^2 × 7^2. That gives 441 exactly 9 divisors: 1, 3, 7, 9, 21, 49, 63, 147, 441. 441's proper divisors total just 300, 141 short of 441, the deficient case most of 441's neighbors share too. 441 is also a perfect square, since 21² = 441. 441 has a digit sum of 9; for 441, the digital root works out to 9. 441: 3, 7, 9 all divide 441 evenly, out of 2-12. 441 is 110111001 in binary and 1B9 in hex; as a Roman numeral it's CDXLI.